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Biomedical subjects

K Fukiyama

Publications and source records attributed to K Fukiyama.

At least 19 recordsLinked to original sources
PubMed2000

Long-term prognosis and incidence of acute myocardial infarction in patients on chronic hemodialysis. The Okinawa Dialysis Study Group.

Mortality from cardiovascular disease is high in chronic dialysis patients. We observed the occurrence of acute myocardial infarction (AMI) in the chronic dialysis population in Okinawa, Japan. A total of 3,741 chronic dialysis patients (2,073 men, 1,668 women) were followed up for 10 years from April 1, 1988, to March 31, 1998. Only definite cases of AMI were registered. Data were compared with AMI registry data obtained from the general population of the same district. The total duration of observation was 15,748.8 patient-years. During the study period, 61 patients (40 men, 21 women) had AMI. The incidence of AMI was 3.9/1,000 patient-years (men, 4.4/1,000 patient-years; women, 3.1/1,000 patient-years). Twenty-four percent of the AMI cases occurred at 12 months after starting dialysis therapy. Mean age at onset of AMI was 60.9 +/- 11. 4 (SD) years; 58.9 +/- 11.4 years in men and 64.7 +/- 10.7 years in women. Survival rates after AMI were 50.8% at 1 month, 45.0% at 6 months, 36.5% at 12 months, and 13.0% at 44 months. Patients with diabetes mellitus (DM) had a greater incidence of AMI and a worse prognosis than patients without DM. The long-term prognosis of AMI was poor in chronic dialysis patients.

Age of Onset↗
PubMed2000

Multiple risk factor clustering of hypertension in a screened cohort.

OBJECTIVE: A family history of hypertension, obesity, diabetes mellitus, hypercholesterolaemia and hypertriglyceridaemia have all been associated with the risk for hypertension. We evaluated whether the clustering of these risk factors increases the risk for hypertension or whether the accumulation of risk factors is associated with the blood pressure level in non-hypertensive subjects. METHODS AND SUBJECTS: We assessed the clinical data and family history of hypertension (in parents and siblings) for 9914 individuals (6163 men and 3751 women, 18-89 years old) who were screened in Okinawa, Japan, in 1997. RESULTS: In 9914 subjects (2465 hypertensive and 7449 non-hypertensive subjects), all the five factors were positively associated with hypertension. The odds ratios (95% confidence interval) for the number of risk factors were 1.88 (1.62-2.18) for one risk factor, 3.06 (2.62-3.57) for two, 5.25 (4.37-6.30) for three, 8.71 (6.48-11.72) for four and 24.48 (8.49-70.56) for five, after adjusting for age, sex, alcohol consumption, cigarette smoking and physical exercise habits. In non-hypertensive subjects, multivariate regression analyses showed that the number of risks was positively correlated with blood pressure; the regression coefficient was 1.96 (P < 0.0001) for systolic blood pressure, and 1.47 (P < 0.0001) for diastolic blood pressure after adjusting for age and sex. CONCLUSIONS: Clustering of risk factors was significantly associated with hypertension. The number of risk factors positively correlated with the blood pressure levels in nonhypertensive subjects. The accumulation of risk factors may play an important role in the pathogenesis of hypertension, and thus the aggregation of risk factors may need to be addressed in primary prevention efforts related to hypertension.

Adult↗
PubMed2000

Incidence and long-term prognosis of initial stroke and acute myocardial infarction in Okinawa, Japan.

We performed a cross-sectional survey of the incidence of stroke and acute myocardial infarction (AMI) in Okinawa, Japan, with a census population of about 1.2 million. A total of 3,644 cases of first-ever stroke and 898 cases of initial AMI were detected. The age-adjusted annual incidence rate of stroke was 105 per 100,000 of the standard population of Japan based on census population taken in 1985, and that of AMI was 26 per 100,000. The case-fatality rate of stroke within 28 days of onset was 12.8%, and that of AMI was 22.2%. Of the stroke cases, 51.4% were diagnosed as brain infarctions, 38.7% as brain hemorrhages, and 9.3% as subarachnoid hemorrhages. The diagnoses of stroke subtypes were confirmed by computed tomography or magnetic resonance imaging in 98.4% of all stroke cases. The long-term prognosis of patients with stroke and AMI was studied by examining their 10-yr survival rates (follow-up rate 89.8%). The cumulative survival rate was 38.2% in brain infarction cases, 40.4% in brain hemorrhage cases, and 38.2% in AMI cases. The 50% reduction of survival had occurred at 2,880 days after onset in brain infarction cases, at 2,764 days in brain hemorrhage cases, and at 2,658 days in AMI cases. In Okinawa, the incidence rate of AMI was still considerably lower than that in the Western population, and the rate of stroke was similar to that in the Western population. The ten-year survival rates were quite similar in AMI and stroke, and both were unexpectedly high.

Adult↗
PubMed2000

Comparison of the effect of blood pressure on the development of stroke, acute myocardial infarction, and end-stage renal disease.

Hypertension is a known risk factor for cardiovascular disease, but few epidemiological studies have examined simultaneously the effect of baseline blood pressure on the development of stroke, acute myocardial infarction (AMI), and end-stage renal disease (ESRD). In 1983, a large, community-based mass screening covered about 14% of the adult population in Okinawa, Japan. The total number of people screened was 107,192 (51,122 men, 56,070 women). We had access to two independent registries of end-organ damage: the Co-operative Study Group of Morbidity and Mortality of Cardiovascular Diseases in Okinawa (COSMO) registry for stroke and AMI, and the Okinawa Dialysis Study (OKIDS) registry for ESRD. The total number of people registered was 4,756 with stroke, 1,059 with AMI, and 641 with ESRD during the study period from April 1, 1988, to March 31, 1991. By using the name, sex, birth date, and ZIP code of registrants, we identified those registrants who were screened in 1983 and had developed stroke, AMI, or ESRD. Hypertension was defined as systolic blood pressure (SBP) of 140 mmHg or higher or diastolic blood pressure (DBP) of 90 mmHg or higher. Other readings were regarded as normotensive. The prevalence of hypertension was 35.8% (N=37,299). The cumulative incidence of stroke, AMI, and ESRD was 154, 21, and 19 subjects among those with SBP < or = 119 mmHg, and 1933, 315, and 71 subjects among those with SBP > or = 160 mmHg. Similarly, the incidence of stroke, AMI, and ESRD was 234, 44, and 25 subjects among those with DBP < or = 69 mmHg and 1980, 381, and 364 subjects among those with DBP > or = 110 mmHg. Hypertension was prevalent in the adult population in Okinawa, Japan, and was a significant predictor of stroke, AMI, and ESRD. However, the effect of blood pressure on target organs differed and was more evident in those with stroke than in those with AMI and ESRD.

Adolescent↗
PubMed2000

Control of blood pressure and lifestyle-related risk factors in elderly Japanese hypertensive subjects.

The aim of this study was to analyze the treatment of elderly hypertensive patients by Japanese physicians specializing in hypertension. We enrolled 939 patients with hypertension who were treated in the outpatient clinics of 11 hospitals in 1995; 793 of these patients (388 men and 405 women; mean age, 66.6+/-9.0 years) received follow-up examinations in 1996, and the data on these patients was used for the present analysis. Blood pressure (BP), body mass index, lifestyle, and laboratory data were analyzed in all patients. The average BP was 143+/-16/81+/-10 mmHg in 1995 and 142+/-15/80+/-10 mmHg in 1996. The patients whose baseline BP was at the level of Grade 2 or 3 in the WHO-ISH classification (n=117) were characterized by a higher women-to-men ratio, higher age, a higher serum total cholesterol concentration, and higher QRS voltage. In these patients, from 1995 to 1996, the average BP significantly decreased, whereas fasting plasma glucose, serum total cholesterol and serum creatinine concentrations showed only negligible changes. In 220 patients (28%), BP was <140/<90 mmHg at both the initial and the follow-up examinations, whereas 351 patients (44%) were hypertensive in both 1995 and 1996. Thirty-three percent of the patients were smokers. More smokers than nonsmokers had had prior cardiovascular events, diabetes mellitus, or overt proteinuria. In conclusion, the average BP level among the patients treated by Japanese physicians specializing in hypertension was somewhat higher than that recommended by WHO-ISH Guidelines (1999). Patient education to control lifestyle-related risk factors, particularly to stop smoking, should be emphasized.

Aged↗
PubMed2000

Non-corresponding effects of an angiotensin-converting enzyme inhibitor on cardiac and vascular hypertrophy in spontaneously hypertensive rats.

Angiotensin-converting enzyme inhibitors (ACEIs) may have different effects on cardiac hypertrophy than on vascular hypertrophy. Arginine vasopressin (AVP) may promote cardiac hypertrophy. Our aims were (1) to simultaneously examine the chronic effects of ACEIs on hypertrophy of the heart and hypertrophy of the coronary and renal interlobular arteries, and (2) to clarify the relation between AVP concentration (AVPC) and cardiac hypertrophy. ACEI (delapril: 30 mg/kg/day) or vehicle (5% arabic gum) was administered in a preventive (4 to 28 weeks of age) or a therapeutic (12-24 weeks of age) protocol in spontaneously hypertensive rats. In both protocols, delapril produced a slight but significant decrease in systolic blood pressure. In the therapeutic protocol, the weight of the left ventricle (mean+/-SE) was lower (p<0.05) in the ACEI group (64+/-2 mg/100 g body weight) than in the control group (69+/-1 mg/100 g body weight). Plasma renin activity was significantly higher in the ACEI group than in the control group in both the preventive (p <0.01) and therapeutic (p<0.01) protocols. In the therapeutic protocol, AVPC was significantly (p<0.05) lower in the ACEI group than in the control group. AVPC was significantly (p=0.02, r=0.46) correlated with the weight of the left ventricle in the therapeutic protocol. For both protocols, no differences were noted between the ACEI and control groups in the vascular hypertrophy of the coronary and renal interlobular arteries. We conclude that (1) the preventive or therapeutic effect of ACEIs on hypertrophy may not be the same in the heart as in the coronary and renal arteries; and (2) AVP was significantly correlated with the left ventricular weight. This indicates that AVP could play a role in the etiology of cardiac hypertrophy in SHR.

Aldosterone↗
PubMed2000

Differences between coronary hyperresponsiveness to ergonovine and vasospastic angina.

The objective of the present study was to investigate the differences between coronary hyperresponsiveness without ischemia and vasospastic angina in an ergonovine provocation test using multivariate analysis. We have sometimes experienced a more than 50% narrowing response of vascular diameter without ischemia in a coronary response to ergonovine. We studied 107 patients with less than 50% stenosis in a coronary arteriogram. Their vascular responses to ergonovine were measured and the patients were divided into three groups, as follows: Group 1 had 50% or less vascular narrowing response without ischemia; Group 2 had a vascular hyperresponsiveness of more than 50% narrowing response without ischemia; and Group 3 experienced a hyperresponsiveness with ischemia. The degree of coronary response was found to be related to smoking, inpaired glucose tolerance (IGT) and the Gensini score by multiple regression analysis. A multiple logistic analysis revealed that the Gensini score and smoking were significant predictive factors for Group 3 (odds ratio: 1.20 and 8.97). The only factor different between Group 2 and Group 1 was gender. The coronary hyperresponsiveness to ergonovine without ischemia differs from vasospastic angina in the degree of coronary atherosclerosis and smoking habits. The patients with hyperresponsiveness had similar characteristics to those with atypical chest pain rather than vasospastic angina, except for a gender difference.

Aged↗
PubMed1999

Serum C-reactive protein (CRP) and risk of death in chronic dialysis patients.

BACKGROUND: The prognosis of chronic dialysis patients is poor, in part due to the high incidence of cardiovascular disease. Malnutrition, such as hypoalbuminaemia, has been shown to be a predictor of death in this group of patients, while serum C-reactive protein (CRP) is a predictor of myocardial infarction and sudden death. Thus, the aim of the present study was to determine of the relationship between CRP and serum albumin concentration, and the value of baseline CRP data in the prediction of death. METHODS: In one of the dialysis units in Okinawa, Japan, baseline CRP data was available (n=163, 95 men and 68 women) in January 1991. These patients were divided into two groups according to their baseline CRP levels, with group 1 consisting of CRP<10 mg/l (n=128) and group 2 of CRP> or =10 mg/l (n=35), and then followed up until the end of 1997. Survival curves were calculated using the Kaplan-Meier method. The statistical significance of the relationship between CRP levels and the risk of death was evaluated by multiple logistic analysis with covariables such as age, sex, diabetes mellitus, serum albumin, and blood pressure. RESULTS: The mean (SD) level of serum albumin was 38 (3) g/l in group 1 and 36 (3) g/l in group 2 (P<0.00001). The 5-year survival rate was significantly poorer in group 2 (44.4%) than in group 1 (82.5%) (P<0.0001). Furthermore, the risk of death was significantly higher in group 2 (relative risk 3.48 (95% confidence interval 1.76-6.89), P<0.0003) by multivariate Cox proportional hazard analysis. CONCLUSIONS: CRP is a significant predictor of death in chronic dialysis patients, independent of serum albumin and other possible confounders. Dialysis patients with high CRP levels should be carefully evaluated and monitored regardless of serum albumin concentrations in the normal range.

Adult↗
PubMed1999

Blood pressure variability as an adverse prognostic risk factor in end-stage renal disease.

BACKGROUND: Prospective and case-control studies show that blood-pressure variability is an independent risk factor for severe organ damage and cardiovascular events in hypertensives. We prospectively studied the association between systolic blood pressure variability and cardiovascular mortality and mortality from all causes in end-stage renal disease patients. METHODS AND RESULTS: The subjects were 144 patients (86 men, 58 women; mean age+/-SD, 52+/-13 years) who underwent dialysis in the same dialysis centre and were examined for blood-pressure variability. The study period was 38 months beginning in January 1995, during which six cardiovascular and seven noncardiovascular fatalities occurred. Coefficient of variation in systolic blood pressure in 1994, as an indicator of systolic blood pressure variability, ranged from 7.8 to 14.6%. Cumulative incidence of death from all causes was related to coefficient of variation in systolic blood pressure. The difference between the maximum and minimum systolic blood pressure (deltaSBP) in 1994 ranged from 44 to 146 mmHg (mean+/-SD, 78+/-13 mmHg) and correlated significantly with coefficient of variation in systolic blood pressure (r = 0.65, P<0.0001). Cox regression analysis was used to identify the independent predictors for mortality. The hazard ratio for death from all causes increased 1.63 times per 1% increase in coefficient of variation in systolic blood pressure (hazard ratio; 95% confidence interval: 1.63; 1.05-2.53) and 1.03 times per 1 mmHg increase in deltaSBP (1.08; 1.03-1.14). CONCLUSION: These results suggest that systolic blood pressure variability may be a significant prognostic factor in end-stage renal disease.

Adult↗
PubMed1999

Seasonal blood pressure and body weight variation in patients on chronic hemodialysis.

AIM: The relation of ambient temperature (AMT) and relative humidity to systolic blood pressure (SBP), diastolic blood pressure (DBP), body weight (BW), and body weight gain between dialysis sessions (DeltaBW) was examined in hemodialysis patients by Fourier analysis. METHODS AND RESULTS: The authors recruited 144 dialysis patients from a hemodialysis center in Okinawa, Japan where there is distinct seasonal variation in monthly AMT but a constant intradiurnal temperature change throughout the year. All patients had been undergoing chronic and regular hemodialysis three times per week. SBP, DBP, and BW before dialysis sessions and DeltaBW were recorded in 1994. Mean monthly Okinawa AMT in 1994 was highest in August and lowest in February and March, and the mean monthly relative humidity in 1994 was highest in June and lowest in January. Mean SBP and DBP were lowest in August and June respectively, and greatest in December. BW was lowest in July and September, and greatest in February and March; DeltaBW was lowest in July and greatest in January. These seasonal patterns were well reproduced by the first Fourier component. The cross-correlation coefficient showed that monthly mean AMT and SBP, DBP, BW, and DeltaBW were correlated with a lag time of 5 or 6 months. The cross correlation coefficient showed that relative humidity and SBP, DBP and DeltaBW were also correlated with a 6-month lag time. In analyzing subgroups of patients according to the presence or absence of antihypertensive medications, a seasonal change was observed in the SBP and DBP of patients not being treated with antihypertensives, and in the DBP of patients taking antihypertensive medications, but not in the SBP of patients taking antihypertensive medications. CONCLUSION: Seasonal variations in SBP, DBP, BW and DeltaBW were evident. AMT and the relative humidity correlated strongly with SBP, DBP, BW and DeltaBW. The clinical implications of these findings in hemodialysis patients warrant further investigation.

Blood Pressure↗
PubMed1999

Sudden death in the general population in Okinawa: incidence and causes of death.

Sudden unexpected death is generally considered to be caused by acute myocardial infarction and/or arrhythmia. To document the incidence and causes of sudden death in Japan, where the incidence of myocardial infarction is low, the present study examined death certificates, hospital records, the forensic medical records, and the police records of residents of the southern part of Okinawa island who died at the age of 20-74 years during a 3-year period from January 1, 1992 to December 31, 1994. Sudden death was defined as death within 24 h from the onset of unexpected symptoms. The study documented 126 (87 men and 39 women) sudden deaths. The crude incidence rate was 0.37/1,000 person per year (0.51 in men and 0.23 in women). According to the death certificates, 78 cases died of heart diseases. However, the cause of death could be determined by examination of all available records in only 64 cases: myocardial infarction in 10, non-ischemic heart diseases in 13, and stroke in 23 cases. Even when the analysis was limited to the cases who died within 1 h from the onset of symptoms, heart disease was the cause of death in only 22% of the cases while the cause of death could not be determined in 53% of the cases. Only 13% of those diagnosed as heart diseases on the death certificate were verified. The agreement rate between the diagnosis reached by the re-evaluation of the records and that on the death certificate was 82% for stroke and 33% for other diseases. In Okinawa, Japan, the frequencies of heart disease and stroke as the cause of sudden death may be similar. Except for stroke, the diagnosis appearing on the death certificate has substantial inaccuracy.

Adult↗
PubMed1999

Low serum cholesterol as a risk factor for hemorrhagic stroke in men: a community-based mass screening in Okinawa, Japan.

The relation between the level of total serum cholesterol and stroke is controversial. The relation between serum total cholesterol and subtypes of stroke was examined in the participants of a community-based mass screening program in Okinawa, Japan. A total of 38,053 subjects, whose serum level of cholesterol had been determined during a mass screening carried out in 1983, were examined to see whether they had experienced stroke during a 3-year period from 1988 to 1991. Of them, 315 subjects aged 33-93 years (174 men, 141 women) had had a stroke during that period. The types of stroke were cerebral infarction in 164, cerebral hemorrhage in 111, subarachnoid hemorrhage in 19, and others in 21. In men, the odds ratio of cerebral hemorrhage was 0.71 (95% confidence interval, 0.55-0.95), and the odds ratio of cerebral hemorrhage associated with serum level of cholesterol < or =167 mg/dl, 168-191 mg/dl, 192-217mg/dl, and > or =218mg/dl were 1.00 (reference), 0.70 (0.38-1.30), 0.77 (0.55-1.08), 0.73 (0.56-0.96), respectively. Lower serum cholesterol was an independent predictor of cerebral hemorrhage in men.

Adult↗
PubMed1999

Divergent effects of beta-blocker therapy on self-estimated and objectively scored activities of daily living.

To identify factors that influence changes in the activities of daily living (ADL) assessed by a standardized scoring system, ADL-20, and factors affecting the self-estimate of the changes in ADL, we conducted a 1-yr follow-up study of 1,163 outpatients aged 50 yr or older. The follow-up rate was 83.1%. A decrease in the ADL score was associated with advancing age and a lower prescription rate of beta-blockers. Analysis of the modalities of ADL revealed an association between a decreasing mobility score and a lower prescription rate of beta-blockers. In patients with impaired ADL at the time of enrollment, worsening of the ADL score was also associated with a lower baseline ADL score and a history of cardiovascular events. The prescription rate of diuretics was lower in patients who exhibited an improvement in ADL score. There was a considerable dissociation between the self-estimate of changes in ADL and the actual change in ADL-20 score. In more than 60% of patients with impaired baseline ADL, the self-estimate of changes was worse than the actual change in the ADL score. The "worse-than-actual" self-estimate of changes in ADL was associated with a higher prescription rate of beta-blockers. Thus, a history of cardiovascular events accelerates the aging-related deterioration of ADL. The use of a beta-blocker may worsen the self-estimate of the changes in ADL, while the actual ADL is preserved or slightly improved during beta-blocker therapy.

Activities of Daily Living↗
PubMed1999

Factors related to impairment of activities of daily living.

OBJECTIVE: We examined the factors related to the impairment of activities of daily living (ADL). METHODS: ADL was evaluated by using ADL-20, which consists of 20 items from 4 major categories of activities; mobility, self-care, instrumental, and communication. The patients' gender, birth date, clinical diagnosis, past history, life styles, physical findings, laboratory data, and details of therapy were also recorded. Patients A total of 1,163 outpatients aged 50 years or older were included. Data from 1,093 patients were analyzed. RESULTS: We divided the subjects into two groups; Group I having full marks of ADL-20 (n=582) and group II exhibiting an impairment of ADL (n=511). Multiple logistic analysis revealed that in both sexes age and stroke were common independent factors related to the impairment of ADL. Other factors associated with impairment of ADL were smoking in men and presence of proteinuria in women. The presence of hyperlipidemia was associated with preservation of the ADL in women. CONCLUSION: The results demonstrated significant associations of smoking in men and the presence of proteinuria in women with the impairment of ADL in elderly Japanese outpatients. There appears to be a sex difference in the risk factors of impairment of ADL.

Activities of Daily Living↗
PubMed1999

[Apical hypertrophic cardiomyopathy followed by midventricular obstruction and apical aneurysm: a case report].

A 72-year-old man presented with apical hypertrophic cardiomyopathy followed by midventricular obstruction and apical aneurysm. Doppler echocardiography revealed an abnormal blood flow from the apical aneurysm to the left ventricular outflow through the obstructive lesion during diastole. Myocardial perfusion scintigraphy showed no ischemic change in the apex. This case suggests that apical aneurysm may not be caused by ischemia, although previous reports showed ischemic degeneration or fibrosis may be a cause of an apical aneurysm.

Aged↗
PubMed1998

Effects of meal ingestion and active standing on blood pressure in patients > or = 60 years of age.

Postprandial hypotension and orthostatic hypotension occur often in elderly patients. In the present study, we examined hemodynamic and humoral responses to meal ingestion and active standing in 20 patients > or = 60 years of age who were free of apparent autonomic and cardiac dysfunction. For a time-control study, water was given instead of a meal to 19 of the 20 patients. After the meal ingestion, there was a fall in systolic blood pressure (BP) in 6 patients of > 20 mm Hg, whereas the fall in systolic BP during the control study was not > 20 mm Hg in any patient. The low-frequency power of the systolic BP wave, an index of peripheral sympathetic activity, was significantly increased only in the patients without postprandial hypotension. The postprandial changes in systolic BP were correlated with the changes in the low-frequency power of the systolic BP wave (r = 0.61; p < 0.01), but they were not correlated with the changes in plasma norepinephrine, insulin, cardiac output, or parameters obtained by the spectral analysis of the RR interval. The systolic BPs in the upright position were comparable after the meal and the water ingestion. Thus, the effects of meal ingestion and upright position on BP are not additive. Dysfunction of peripheral sympathetic control of vascular tone may contribute to the postprandial hypotension in elderly patients.

Aged↗
PubMed1998

Contribution of alpha 2-adrenoceptors in caudal ventrolateral medulla to cardiovascular regulation in rat.

The inhibitory action of alpha 2-agonists on the cardiovascular neurons has been elucidated in the rostral ventrolateral medulla (RVLM) but not in the caudal ventrolateral medulla (CVLM). Our study aimed to clarify whether microinjection of clonidine into the CVLM elicits any cardiovascular effect and whether endogenous alpha 2-adrenoceptor-mediated mechanisms contribute to the tonic activity of the CVLM neurons. In male Sprague-Dawley rats (7-9 wk old, 270-320 g) anesthetized with urethan, unilateral microinjection of 8 nmol of clonidine into the CVLM (n = 10) increased mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) by 12.1 +/- 1.8 mmHg (mean +/- SE, P < 0.01) and 25.8 +/- 4.8% (P < 0.01), while heart rate (HR) remained unaltered. Unilateral microinjection of 2 nmol of SKF-86466, a selective blocker of the alpha 2-adrenoceptors, into the CVLM (n = 10) decreased MAP, HR, and RSNA (-11.6 +/- 2.6 mmHg, -26 +/- 7 beats/min, and -15.3 +/- 1.7%, respectively, P < 0.01 for each). Artificial cerebrospinal fluid caused neither a cardiovascular effect nor a sympathetic response. Prior injection of SKF-86466 into the ipsilateral CVLM attenuated the effects of clonidine. Bilateral microinjection of muscimol into the RVLM abolished the effects of both clonidine and SKF-86466 injected into the CVLM. The pressor and sympathoexcitatory effects of clonidine injected into the CVLM suggest a neuroinhibitory action of the drug on the CVLM neurons. In addition, the depressor and sympathoinhibitory effects of SKF-86466 injected into the CVLM indicated that activation of alpha 2-adrenoceptors by endogenous ligand inhibits CVLM neurons. The effects of clonidine and the alpha 2-adrenoceptor antagonist in the CVLM require the integrity of the RVLM.

Adrenergic alpha-Agonists↗